A motor can convert electric energy into mechanical energy by using a copper coil, also known as stator winding, to produce a rotating magnetic field, which acting on a rotor, forms a rotary torque driven by magnetoelectricity. Motors are widely used in the industries, especially in compressors. However, motor loss has been one of the factors that affect the performance of a motor. Currently, motor loss mostly results from the rotor. When the rotor is running at a high speed, it will generate a large magnetic flux and easily cause a high magnet temperature and demagnetizes the magnet. This may degrade the overall performance of the compressor. Generally, prior art in this field relies on cooler oil flowing through several oil holes in the rotor to reduce the temperature of the rotor magnet to cool the magnet.